1. Field of the Invention
The present invention relates to an apparatus and method for detecting a horizon in a sea image, and more particularly, to an apparatus and method for detecting a horizon which is necessary to detect a camera movement when compositing sea images in a marker-free sea-image camera tracking system.
The present invention is drawn from a study conducted as a IT new driving force key technology development project of Ministry of Information and Communication (MIC), and Institute for Information Technology Advancement (IITA) [task reference number: 2005-S-003-02, task name: Photo-Realistic Digital Image Content Production Software].
2. Description of the Related Art
A compositing technique of computer graphics (CG) and real image is considerably developed in the movie industry and augmented reality. A camera movement at the moment of shooting should be detected for natural composition. It requires great effort and takes a lot of time to perform the composition in each frame by manual manipulation.
Recently, instead of the manual manipulation, various commercial softwares, such as Shake, Boujou, Matchmover, Combustion, etc., are used for image composition. The camera movement is calculated by detecting distinctive features between adjacent images in a series of images, matching the distinctive features, and using their correlation. However, in the case of a sea image having no distinctive features, the camera movement is calculated by floating marker buoys on the sea and using the maker buoys as the distinctive features like in a movie of “TROY”. In this case, when the movie is shot, the marker buoys must be connected to ships. In addition, unlike a long-range shot is taken from a helicopter, when a close-range shot is taken from a neighboring ship, it is a problem the marker buoys are heavily moved by waves. Accordingly, the image composition is very difficult in most cases.
Information about a tilt, yaw, etc. of a camera can be obtained using horizon information without markers in the sea image. In general, a horizon of the sea image can be detected using the Radon or Hough transform, which is used to detect a straight line from a sea image. However, the horizon cannot be detected using the line detection process because the horizon is blurred due to wet fog when weather condition is bad.